Device and method for applying adhesive to materials such as strands

ABSTRACT

A device and method for applying adhesive to materials, such as elastic strands, used in the production of nonwoven products. Generally, a nozzle is provided and includes a liquid discharge orifice configured to discharge a bead of liquid adhesive. First and second pattern air discharge orifices are associated with the first liquid discharge orifice to vacillate or oscillate the adhesive bead. First and second cleaning and stabilizing air discharge orifices are also associated with the first liquid discharge orifice. These latter air discharge orifices keep airborne contaminants away from the associated liquid discharge orifice and also stabilize the oscillation of the adhesive bead in a single plane. A method in accordance with the invention includes using the nozzle to dispense a vacillating bead of adhesive onto a strand of material.

This application claims the priority of Japanese Patent Application No.2000-117263 filed Mar. 14, 2000, the disclosure of which is hereby fullyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention pertains to a device and a method for applying anadhesive to materials such as strands, which are used by subsequentlybonding them to a substrate.

BACKGROUND OF THE INVENTION

The structure of a disposable diaper is disclosed, for example, inJapanese Patent Kokai No. 11[1999]-285,510. In the structure of thisdisposable diaper an elastic strand(s) is provided at various locationsincluding at the bending section and free ends of a sheet so as to forma barrier. In the process of producing disposable diapers with this kindof structure, the disposable diapers are produced through steps such asapplying an adhesive to elastic strand material being fed continuously,then bonding the elastic strand material to a base or substrate materialwhich forms the main part of the diaper and which is also fedcontinuously, and finally in a subsequent step cutting the resultingproduct into individual diapers.

Not only in the production of the aforesaid disposable diapers but alsoin the process of producing, for example, disposable surgical gowns tobe used in operating rooms, elastic strand material and nonwoven orwoven fabrics are bonded together with an adhesive. Also, in a processof this kind, the materials to be coated with the adhesive are notalways elastic members, there are cases where strand materials with nostretching properties are coated with the adhesive and bonded to asubstrate. Accordingly, the term “strand material” or similar terms asused in the present specification are meant to also include both elasticmaterials such as elastic yarn and nonelastic material.

Furthermore, the cross-sectional shape of the strand material is notonly circular but includes various shapes such as elliptic, square, andrectangular, and the thickness also ranges from the order of hundredthsof a millimeter to the order of several millimeters. Thus, there are noparticular limitations with regard to the shape and thickness of thestrand material. As the adhesive to be used, a hot-melt adhesive is usedin many cases, but other types of adhesive can be used as well.

A conventional device and method for applying an adhesive to strandmaterial in the process of producing the aforesaid disposable diapers orother products will now be explained with reference to FIGS. 9-12. FIG.9 shows a front view of the conventional coating device. FIG. 10 shows avertical sectional view of the conventional coating device. FIG. 11shows an expanded view of the leading end portion of FIG. 10. FIG. 12shows an enlarged view of encircled portion D of FIG. 9.

In FIGS. 9-12, coating device 51 includes a valve mechanism 65 which isopened and closed by operating air 80. A gun body 52 forms the coatingdevice 51; a cylinder block 53 is attached with a plurality of bolts 54to the top of the gun body 52, and a piston 55 moves up and down and islocated inside the cylinder block 53. A valve stem 56 is fastened to thepiston 55 and is extended into a liquid chamber 59 through a seal block57. A seal member 58 is provided in the gun body 52, and includes avalve ball 60 at the leading end.

Furthermore, a valve seat member 62 that has an outlet 62 a is attachedwith a plurality of bolts 63 to the lower part of the gun body 52. Ascrew 62 b is provided in the lower outer diameter section of the valveseat member 62. The valve ball 60 is at the leading end of the valvestem 56 and the valve seat member 62 forms the valve mechanism 65. Aspring 75 is placed between the large-diameter section at the leadingend of the valve stem 56 and the underside of the seal block 57, andcloses the valve mechanism 65 by forcing the valve stem 56 downward atall times.

A nozzle member 66 has a flange section 66 a. A cap nut 67 is providedwith a small-diameter section 67 a to be engaged with the flange section66 a of the nozzle member 62 and a screw section 67 b to be engaged withthe screw 62 b of the valve seat member 62. The nozzle member 66 isattached to the lower end of the valve seat member 62 by engaging thesmall-diameter section 67 a of the cap nut 67 with the flange section 66a, and attaching the screw section 67 b of the cap nut 67 over the screw62 b.

Moreover, a flat section 66 b is formed in the nozzle member 66, and anozzle plate 68 is fastened with a plurality of bolts 69 to the flatsection 66 b. A through-hole 66 c communicates with the outlet 62 of thevalve seat member 62. A horizontally long groove 66 d extends in thehorizontal direction in communication with the through-hole 66 c andopens to the flat section 66 b, and three branched nozzle grooves 66 ecommunicate with the horizontal groove 66 d in the nozzle member 66. Thehorizontal groove 66 d and the nozzle grooves 66 e are combined in sucha way that the nozzle plate 68 covers the open section of the grooves.The nozzle groove 66 e is open at the lower end and a nozzle hole 70couples with the nozzle plate 68.

The lower ends of the nozzle member 66 and the nozzle plate 68 haveexactly the same shape, and are formed like teeth of a comb stretchingto below the nozzle hole 70. An inverted V-shape groove 61 with itslower end slightly spreading is formed with the nozzle hole 70 at thecenter. This groove 61 plays a role as a guide for the strand material14 to be coated with the adhesive. An example of the conventionalcoating device shown in the figures is a device wherein three nozzleholes 70 are formed so as to apply three strands 14 simultaneously byone coating device 51. The device is not limited to this and may haveone nozzle hole or many more nozzle holes to enable the coating of oneor more strands.

To return to the explanation of the gun body 52, the gun body 52 isprovided with an air through-hole 52 a for feeding operating air 80 tothe underside of the piston 55, and an adhesive through-hole 52 b forfeeding an adhesive 81 to the liquid chamber 59. The gun body 52 isfastened with a plurality of bolts 72 to a manifold 71. The manifold 71is provided with an air feed hole 71 a that communicates with the airthrough-hole 52 a of the gun body 52, and an adhesive feed hole 71 bthat communicates with the adhesive through-hole 52 b. An operating airfeed device 73 is connected with the air feed hole 71 a of the manifold71 via a tubular path such as a hose, and an adhesive feed device 74 isconnected with the adhesive feed hole 71 b of the manifold 71 via atubular path such as a hose.

In the coating device thus constructed, the adhesive 81 fed from theadhesive feed device 74 is stored in the liquid chamber 59 through theadhesive feed hole 71 b of the manifold 71 and the adhesive through-hole52 of the gun body 52. If operating air 80 is fed from the operating airfeed device 73 to the underside of the piston 55, the piston 55 andvalve stem 56 operate upward against the force of the spring 75, and thevalve mechanism 65 is opened.

While the valve mechanism 65 is open, the adhesive 81 in the liquidchamber 59 is extruded from the nozzle hole 70 via through-hole 66 c ofthe nozzle member 66 and the horizontally long groove 66 d from theoutlet 62 a of the valve seat member 62, and applied to the surface ofstrand material 14. In this case, the nozzle hole 70, the topmost partof the inverted V-shape grooves 61 of the nozzle member 66 and nozzleplate 68 are in contact with the strand material 14. The strand material14 is coated with the adhesive 81 and adhered to the substrate in anot-illustrated device in a later step. If the feeding of operating air80 is stopped and the air pressure on the underside of the piston 55 isreleased, the valve mechanism 65 closes by the force of the spring 75,and the extrusion of adhesive 81 from the nozzle hole 70 stops. Theadhesive can be applied intermittently by the opening and closingoperations of the valve mechanism 65.

In another known device, the adhesive is dispensed in a spiral patterntowards the strand material. One or multiple strands can be used and theadhesive can be dispensed from one or multiple nozzles. The spiralpattern of adhesive wraps completely around the strand material whilethe strand material is still separate from the substrate. The operatingcharacteristics of this system such as adhesive pressure, air pressure,distance from the dispenser nozzle to the strand material can all bevaried to control the extent of the wrap around and to control theamount of adhesive captured by the strand material. It is well known tothose of ordinary skill in the field that the strand material cancapture substantially all of the spiral adhesive or some portion of thespiral adhesive can pass by the strand material to contact thesubstrate. This known device is described in U.S. Pat. No. 4,842,666 andas shown in “Adhesive and Powder Application Systems for the NonwovenIndustry”, Nordson Corporation, October 1992, both of which areincorporated herein by reference.

The first aforementioned adhesive coating device is known to have thefollowing problems. If the thickness or shape of the strand materialchanges, the size of the inverted V-shape groove also must be changed,and this leads to troublesome operation and extra time. Furthermore,since the strand material is coated with the adhesive in constantcontact with the nozzle hole and inverted V-shape groove while beingtransferred at high speed (usually 70-400 m/minute), stress develops inthe strand material. As a result, the strand material can be severed, orthe grooves of the nozzle member can wear during lengthy operation andbecome larger than the diameter of the strand material. In some casesthe adhesive drips from the strand material onto the substrate.

Furthermore, although the adhesive is applied sufficiently to the areafacing the nozzle hole of the strand material, the adhesive is notapplied sufficiently to the opposite underside, and this can result inpoor adhesion. Moreover, because fiber products are being transferred athigh speed, the operating environment is such that fine fibrous dust ismore easily formed by friction between the fiber products and mechanicaldevices. This fine airborne dust adheres readily to the nozzle holesections, and this adhered dust piles up over time, solidifies, anddestabilizes the coating process. In an extreme case, the extrusion ofthe adhesive becomes obstructed and the strand material can be severed.

Yet another problem has been that, when applying the adhesiveintermittently by controlling the opening and closing of the valvemechanism, the adhesive remaining downstream from the valve mechanism isinevitably drawn out by the strand material even after the valvemechanism is closed, and a poor final coating results.

In the second known device mentioned above, the spiral pattern issometimes difficult to control across the length of the strand material.This can lead to uneven or nonuniform application of the spiral bead ofadhesive to the strand material.

Thus, the invention of the present application was developed in view ofthe above-mentioned problems, and is aimed at providing a device and amethod for applying an adhesive to material such as strand material,which requires no change in the device even if the thickness or shape ofthe strand material is changed, by installing the coating device innoncontact with the strand material. The present invention can achievegood all-around attachment of the adhesive, and moreover can carry outhigh-quality application of the adhesive with clean nozzles without anyadhesion of dust and while maintaining a more uniform back and forth orvacillating adhesive bead pattern.

SUMMARY OF INVENTION

The present invention generally provides a nozzle for dispensing aliquid adhesive to materials, such as strand materials or flatsubstrates, used in the manufacture of nonwoven products. The nozzleincludes a nozzle body having a liquid supply passage and a first liquiddischarge orifice in fluid communication with the liquid supply passage.The first liquid discharge orifice extends along a first axis and isconfigured to discharge a first bead of the liquid adhesive. First andsecond pattern air discharge orifices in the nozzle body are associatedwith the first liquid discharge orifice. In addition, first and secondcleaning and stabilizing air discharge orifices in the nozzle body arealso associated with first liquid discharge orifice. The first andsecond pattern air discharge orifices and the first and second cleaningand stabilizing air discharge orifices are arranged around the firstliquid discharge orifice at 90° alternating positions. That is, thefirst and second pattern discharge orifices are arranged 180° apart onopposite sides of the first liquid discharge orifice and the first andsecond cleaning and stabilizing air discharge orifices are arranged 180°apart on opposite sides of the first liquid discharge orifice atpositions 90° from the first and second pattern air discharge orifices.

The two sets of air discharge orifices have different advantageousfunctions each in association with the corresponding liquid dischargeorifice. The pattern air discharge orifices vacillate the first bead ofadhesive back and forth in a vacillating plane containing the first andsecond pattern air discharge orifices. The first and second cleaning andstabilizing air discharge orifices emit jets of air in a directionparallel to the first axis to clear airborne contaminants, such as dust,away from the first liquid discharge orifice and to stabilize the firstbead of adhesive in the vacillation plane. Thus, not only do thecleaning and stabilizing air discharge orifices clean the nozzle ofcontaminants, such as dust which may clog the liquid discharge orifice,they also help maintain the vacillating adhesive bead in a single plane,which is generally a plane perpendicular to the machine direction of thematerial. This ensures a more uniform adhesive bead pattern and,therefore, more accurate and consistent bead placement.

More specifically, the nozzle may comprise more than one liquiddischarge orifice and associated sets of pattern air discharge orificesand cleaning and stabilizing air discharge orifices, depending on theapplication needs. Further, the nozzle is advantageously coupled to anon/off dispensing module including a valve mechanism for selectivelyallowing and preventing the flow of adhesive from the liquid dischargeorifice or orifices. The first and second pattern air discharge orificespreferably converge toward the axis defining the associated liquiddischarge orifice, while the first and second cleaning and stabilizingair discharge orifices are preferably parallel to the axis of theassociated liquid discharge orifice. In addition, the liquid dischargeorifice preferably opens on the apex of a projecting nozzle portion,while the first and second pattern air discharge orifices preferablyopen on the base of the projecting nozzle portion. The first and secondcleaning and stabilizing air discharge orifices open on the apex aswell, directly adjacent the associated liquid discharge orifice.

A method of applying an adhesive bead in accordance with the inventioncomprises moving a strand of material in a linear direction andpositioning the liquid discharge orifice of the nozzle spaced apart fromthe strand of material. An adhesive bead is extruded from the liquiddischarge orifice toward the strand of material and first and secondpattern air jets are discharged from the nozzle to vacillate theadhesive bead back and forth in a vacillation plane while thevacillating adhesive bead attaches to the strand of material. Cleaningand stabilizing air jets are discharged from the first and secondcleaning and stabilizing air jet orifices to clear airborne contaminantsaway from the liquid discharge orifice and to stabilize the vacillatingbead of adhesive in the vacillation plane. In another aspect of themethod, the first and second cleaning and stabilizing air jets arepreferably directed at a lower pressure than the first and secondpattern air jets. In addition, the first and second cleaning andstabilizing air jets may be discharged intermittently or continuously,while the first and second pattern air jets are preferably directed in acontinuous manner to produce the vacillating pattern. The cleaning andstabilizing air jets may be continued after the adhesive bead extrusionhas stopped to continue to clear away airborne contaminants from theliquid discharge orifice.

These and other objects, advantages and features of the invention willbecome more readily apparent to those of ordinary skill in the art uponreview of the following detailed description taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a coating device according to the presentinvention.

FIG. 2 is a vertical sectional view of a coating device according to thepresent invention.

FIG. 3 is a diagram of the nozzle block seen from side A in FIG. 2.

FIG. 4 is a diagram of the nozzle block seen from side B in FIG. 2.

FIG. 5 is a sectional view along C—C of FIG. 3.

FIG. 6 is a base view of the nozzle block.

FIG. 7 is a schematic diagram which shows the manner of the adhesivebeing applied.

FIG. 8 is a schematic diagram which shows the manner of the adhesivebeing applied.

FIG. 9 is a front view of a conventional coating device.

FIG. 10 is a vertical sectional view of a conventional coating device.

FIG. 11 is an expanded view of the leading end part of FIG. 10.

FIG. 12 is an expanded view of part D of FIG. 9.

DETAILED DESCRIPTION

The preferred embodiment of carrying out the present invention will nowbe described. First, an adhesive fed from a well-known adhesive feeddevice is extruded as a continuous bead from an adhesive dischargenozzle installed above a long strand of material traveling at high speedin noncontact with said material, by opening the valve mechanism of acoating device. Pattern air is jetted from two pattern air jet nozzlesprovided on both sides of the adhesive discharge nozzle onto thecontinuous adhesive beads extruded from the adhesive discharge nozzle,the pattern air comes into contact with the adhesive beads and causesthe adhesive beads to begin an oscillating or vacillating motion. Inthis disclosure, the terms oscillating and vacillating are synonymous.This vacillating motion swings in the form of a wave centered around theadhesive discharge nozzle in the direction of the pattern air jetnozzles.

The oscillated adhesive beads are deposited on the surface of the strandmaterial so as to straddle the traveling strand in the crossingdirection. Accordingly, the position of the pattern air jet nozzlesrelative to the adhesive discharge nozzle must be located in thedirection of crossing the traveling strand material. The adhesive thusdeposited on the surface of the strand material begins a fluid movementas a viscous liquid after the deposition, and makes its way around thestrand material by drooping to the underside. The bead also flattensout, so that the adhesive is applied all around the strand material soas to enwrap it.

The above operations are performed while jetting cleaning airintermittently or continuously from the cleaning air jets providedadjacent to the front side and rear side of the adhesive dischargenozzle, thereby enabling continuous operation. In other words, theproblem of airborne fibrous particles adhering to the nozzle holes,piling up and solidifying with the passage of time is avoided. This canprevent destabilizing the coating process and obstructing the extrusionof the adhesive. Furthermore, when the cleaning air is jettedcontinuously, irregular swings of the adhesive can be prevented, and arectifying or stabilizing effect such as to make the bead-form adhesiveswing regularly in the right and left directions is achieved.

It is desirable to adjust the discharge pressure of the cleaning air toa pressure lower than the discharge pressure of the pattern air duringthe extrusion of the adhesive. However, the discharge pressure of thecleaning air can be raised while the valve mechanism is closed, i.e.,the extrusion of the adhesive is stopped, and thereby the adhesion ofdust is prevented more effectively.

The present invention will now be described in concrete terms with theuse of figures which show an actual example of the present invention.Here, the present actual example uses a structure for applying anadhesive to three strand materials simultaneously with one coatingdevice, but the present invention is not limited to this example.

In FIGS. 1 and 2, the coating device 1 has a structure with a valvemechanism 15 which is opened and closed by operating air 30.Specifically, a gun body 2 forms the coating device 1, and a cylinder 2a is formed in the upper part of the gun body 2 and a piston 5 moves upand down and is located inside the cylinder 2 a. A piston cover 3 isattached with a plurality of bolts 4 to the top of the gun body 2. Aspring 25 forces the piston 5 downward at all times.

A valve stem 6 is fastened to the piston 5, and the valve stem 6 extendsinto a liquid chamber 9 through seal members 7 and 8 provided in asmall-diameter section in the gun body 2. An adapter 12 is attached witha plurality of bolts 13 to the lower part of the gun body 2. A valveseat part 12 a leading to the liquid chamber 9 and an adhesivethrough-hole 12 b downstream from the valve seat part 12 a are formedinside the adapter 12. The adhesive through-hole 12 b is open to a flatsection 12 c of the adapter 12, with its lower part bent in an L-shape.The valve stem 6 and valve seat part 12 a of the adapter 12 comprise thevalve mechanism 15. The valve mechanism 15 is kept closed at all timesby the force of the spring 25.

A nozzle block 10, and a nozzle holding plate 11 are stacked andattached with a plurality of bolts 19 to the flat section 12 c of theadapter 12. The configuration of the nozzle block 10 is shown in detailin FIGS. 3-6. The nozzle block 10 is provided with attaching holes 10 afor the bolts 19. A triangular groove 10 b for an adhesive 31 is formedon side A, and three pipe-shaped nozzle members 16 communicating withthe triangular groove 10 b are provided so as to open to the triangulargroove 10 b by fixing a neck part 16 b firmly in the nozzle block 10 bymeans such as pressure insertion, brazing, or welding. Furthermore, thenozzle member 16 opens its leading end as an adhesive discharge nozzleor orifice 16 a to a protrusion 10 c that protrudes on the underside ofthe nozzle block 10. The adhesive through-hole 12 b of the adapter 12opens to the top of the triangular groove 10 b.

A through-hole 10 d for pattern air 32 extends through the nozzle block10. The through-holes 10 d communicate with a pattern air groove 10 e onside B of the nozzle block 10. The pattern air groove 10 e communicateswith pattern air jet nozzles or orifices 10 f which open to both sidesof each adhesive discharge nozzle or orifice 16 a on the underside ofthe nozzle block 10. The pattern air nozzles 10 f may be bored in thevertical direction, but good results can be obtained if they are boredso as to adjust the angle Θ to the adhesive discharge nozzle 16 a in therange of 10-20 degrees. Furthermore, a through-hole 10 g for cleaningair 33 extends through the nozzle block 10. The through-holes 10communicate with a cleaning air groove 10 h on side B of the nozzleblock 10. The cleaning air groove 10 h further communicates withcleaning and stabilizing air jet orifices 10 i which are open in acrescent shape in front and behind the nozzle member 16.

The nozzle block 10 is stacked with the nozzle holding plate 11 andattached to the flat part 12 c of the adapter 12. The triangular groove10 b provided on side A of the nozzle block 12 forms a space that isclosed by the flat part 12 c of the adapter 12, and functions as a pathfor the adhesive 31. The pattern air groove 10 e and cleaning air groove10 h provided on side B form grooves closed by the nozzle holding plate11, and function as a pattern air path and a cleaning air path,respectively.

An operating air through-hole 2 b communicates with the cylinder 2 abelow the piston 5 and an adhesive through-hole 2 c communicates withthe liquid chamber 9. The gun body 2 is fastened together with theadapter 12 with a plurality of bolts 22 to a manifold 21. Furthermore,the adapter 12 is provided with a horizontally long groove 12 d forpattern air 32 and a horizontally long groove 12 e for cleaning air 33on the side meeting the manifold 21. The horizontally long groove 12 dis provided with two pattern air through-holes 12 f that communicatewith two through-holes 10 d of the nozzle block 10. The horizontallylong groove 12 e is provided with two cleaning air through-holes 12 gthat communicate with two through-holes 10 g of the nozzle block 10,though only one air through-hole is shown for each in FIG. 2.

The manifold 21 is provided with an operating air feed hole 21 a thatcommunicates with the operating air through-hole 2 b and an adhesivefeed hole 21 b that communicates with the adhesive through-hole 2 c. Apattern air feed hole 21 c communicates with the horizontally longgroove 12 d and a cleaning air feed hole 21 d communicates with thehorizontally long groove 12 e provided in the adapter 12. The operatingair feed hole 21 a, pattern air feed hole 21 c, and cleaning air feedhole 21 d are connected via a tubular path such as a hose to an air feedcontrol device 23 equipped with the function to regulate the pressure,flow rate, and temperature of the air and the function of on and offcontrol, these functions working independently for each amount of air.The adhesive feed hold 21 b is connected via a tubular path such as ahose to an adhesive feed device 24 equipped again with the function tocontrol pressure, flow rate, etc.

The action of the coating device 1 thus constructed will be explainedbelow. First, the adhesive 31 fed from the adhesive feed device 24 isstored in the liquid chamber 9, after passing through the adhesive feedhole 21 b of the manifold 21, and the adhesive through-hole 2 c of thegun body 2. If the operating air 30 fed from the air feed control device23 is fed into the cylinder 2 a below the piston 5 via the operating airfeed hole 21 a of the manifold 21 and the operating air through-hole 2 bof the gun body 2, the piston 5 and valve stem 6 move upward against theforce of the spring 25, and the valve mechanism 15 is opened.

The adhesive 31 in the liquid chamber 9 is extruded in the form ofcontinuous beads from the adhesive discharge nozzles 16 a of the nozzlemember 16 through the adhesive through-hole 12 b of the adapter 12 andthe triangular groove 10 b of the nozzle block 10, while the valvemechanism 15 is open. Pattern air 32 fed from the air feed controldevice 23 is jetted from the pattern air jet nozzles 10 f through thepattern air feed hole 21 c of the manifold 21, the pattern airthrough-hole 12 f of the adapter 12, and the through-holes 10 d andpattern air groove 10 e of the nozzle block 10. The bead-form adhesive31 begins a swing motion from side to side in a vacillation plane underthe influence of the pattern air 32 as shown in FIG. 7.

The adhesive 31 is swung in the direction of crossing for the movingstrand material 14 which is the material to be coated. The adhesive isapplied to the surface of the strand material 14 so as to straddle thestrand material 14 which is continuously transferred in noncontact belowthe adhesive discharge nozzle 16 a. The adhesive 31 is deposited on thesurface of the strand material 14 and begins a fluid movement as aviscous liquid after deposition, and makes its way to the underside ofthe strand material 14 and also flattens out to form a film, so that theadhesive is applied all around the strand material 14 so as to enwrap itas shown in FIG. 8. The strand material 14 coated with the adhesive isbonded further downstream with a substrate 28 on a roll 29.

These operations are performed while jetting cleaning air 33 from thecleaning and stabilizing air jet orifices 10 i in crescent shapedorifices provided adjacent to the front side and rear side of theadhesive discharge nozzle 16 a. The cleaning air 33 fed from the airfeed control device 23 is jetted from the cleaning and stabilizing airjet orifices 10 i through the cleaning air feed hole 21 d of themanifold 21, the cleaning air through-hole 12 g of the adapter 12, andthe through-holes 10 g and the cleaning air groove 10 h of the nozzleblock 10.

The jetting of cleaning air 33 prevents fine fibrous dust floating inthe air from sticking around the adhesive discharge nozzles 16 a, andenables stable application of the adhesive for long periods of time.This cleaning air jetting may be continuous or intermittent. If thecleaning air is jetted continuously, a rectifying effect such as to makethe bead-form adhesive swing regularly in the right and left directionsby preventing irregular swings of the adhesive is also achieved.Furthermore, it is desirable to adjust the discharge pressure of thecleaning air to a pressure lower than the discharge pressure of thepattern air. The discharge pressure of the cleaning air can be raisedwhile the valve mechanism is closed, i.e., the extrusion of the adhesiveis stopped, and thereby the adhesion of dust is prevented moreeffectively. Moreover, according to test results, it is desirable toadjust the distance H from the leading end of the adhesive dischargenozzle 16 a to the strand material 14 to 5-20 millimeters.

To stop the discharge of the adhesive, the operating air 30 being fed tothe underside of the piston 5 is released by the operation of the airfeed control device 23, then the piston 5 and the valve stem 6 movedownward by the force of the spring 25, and the valve mechanism 15closes and the dis-charge of the adhesive stops. Thus, the open and shutoperation of the valve mechanism 15 can achieve intermittent applicationof the adhesive.

TEST EXAMPLE

Many tests of applying an adhesive to a strand material were repeatedunder the following conditions, and good results were obtained in allthe tests. The conditions were as follows:

(1) strand material used as the substrate: strand elastic, thickness 560denier (diameter about 0.28 mm), traveling speed 150-170 m/minute.

(2) Type of adhesive used: product No. H-6830 from Nitta Findley Co.,Ltd. and product No. HE-1 from Japan N.S.C. Co., Ltd., both beingrubber-based hot-melt adhesives.

(3) Melting temperature of adhesive upon heating: 150° C. for H-6830 and160° C. for HE-1.

(4) Distance from the leading end of the adhesive discharge nozzle tothe workpiece: 5-20 mm.

(5) Diameter of the adhesive discharge nozzle: 0.6 mm.

(6) Discharge pressure of the adhesive: 7-14 kg/cm².

(7) Diameter of pattern air jet nozzle: two diameters, 0.46 mm and 0.50mm.

(8) Pressure of pattern air: 0.3-1.0 kg/cm².

(9) Area of cleaning air jet: approximately equal to the opening area ofthe pattern air jet nozzle.

(10) Pressure of cleaning air: 0.1-0.8 kg/cm², continuous andintermittent jetting.

According to the device and method of the present invention of applyingan adhesive to strand materials, the coating device is placed innoncontact with the strand materials, as described above, and thereby adevice and a method for applying an adhesive to strand materials isprovided. The generation of stretching stress in the strand materials orthe severing of these materials as sometimes seen in contact applicationaccording to one known conventional technique can be avoided. No changeis required in the device even if the thickness and shape of the strandmaterial is changed. The all-around attachment of the adhesive is good.Moreover, high-quality coating of the adhesive can be achieved withclean nozzles with no adhesion of dust and with accurate, uniformplacement of the adhesive.

While the present invention has been illustrated by a description of apreferred embodiments and while these embodiments have been described insome detail, it is not the intention of the Applicant to restrict or inany way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. The various features of the invention may be usedalone or in numerous combinations depending on the needs and preferencesof the user. This has been a description of the present invention, alongwith the preferred methods of practicing the present invention ascurrently known. However, the invention itself should only be defined bythe appended claims, wherein.

1. A nozzle for dispensing a liquid adhesive to strand materials used inthe manufacture of nonwoven products, comprising: a nozzle body having aliquid supply passage and a first liquid discharge orifice in fluidcommunication with said liquid supply passage, said first liquiddischarge orifice extending along a first axis and configured todischarge a first bead of the adhesive, first and second pattern airdischarge orifices in said nozzle body and associated with said firstliquid discharge orifice, said first and second pattern air dischargeorifices arranged 180° apart on opposite sides of said first liquiddischarge orifice and configured to direct pressurized pattern air atthe first bead of adhesive discharged through said first liquiddischarge orifice thereby vacillating the first bead of adhesive backand forth in a vacillation plane containing said first and secondpattern air discharge orifices, and first and second cleaning andstabilizing air discharge orifices in said nozzle body and associatedwith said first liquid discharge orifice, said first and second cleaningand stabilizing air discharge orifices arranged 180° apart on oppositesides of said first liquid discharge orifice and positioned 90° fromsaid first and second pattern air discharge orifices, said first andsecond cleaning and stabilizing air discharge orifices configured todirect pressurized cleaning and stabilizing air in a direction parallelto said first axis to clear airborne contaminants away from said firstliquid discharge orifice and to stabilize the first bead of adhesive insaid vacillation plane.
 2. The nozzle of claim 1, wherein said nozzlebody further comprises: a second liquid discharge orifice in fluidcommunication with said liquid supply passage, said second liquiddischarge orifice extending along a second axis and configured todischarge a second bead of the adhesive, third and fourth pattern airdischarge orifices in said nozzle body and associated with said secondliquid discharge orifice, said third and fourth pattern air dischargeorifices arranged 180° apart on opposite sides of said second liquiddischarge orifice and positioned in said vacillation plane, said thirdand fourth pattern air discharge orifices configured to directpressurized pattern air at the second bead of adhesive dischargedthrough said second liquid discharge orifice thereby vacillating thesecond bead of adhesive back and forth in said vacillation plane, andthird and fourth cleaning and stabilizing air discharge orifices in saidnozzle body and associated with said second liquid discharge orifice,said third and fourth pattern air discharge orifices arranged 180° aparton opposite sides of said second liquid discharge orifice and positioned90° from said third and fourth pattern air discharge orifices, saidthird and fourth cleaning and stabilizing air discharge orificesconfigured to direct pressurized cleaning and stabilizing air in adirection parallel to said second axis to clear airborne contaminantsaway from the second liquid discharge orifice and to stabilize thesecond bead of adhesive in said vacillation plane.
 3. The nozzle ofclaim 2, wherein said nozzle body further comprises: a third liquiddischarge orifice in fluid communication with said liquid supplypassage, said third liquid discharge orifice extending along a thirdaxis and configured to discharge a third bead of the adhesive, fifth andsixth pattern air discharge orifices in said nozzle body and associatedwith said third liquid discharge orifice, said fifth and sixth patternair discharge orifices arranged 180° apart on opposite sides of saidthird liquid discharge orifice and positioned in said vacillation plane,said fifth and sixth pattern air discharge orifices configured to directpressurized pattern air at the third bead of adhesive discharged throughsaid third liquid discharge orifice thereby vacillating the third beadof adhesive back and forth in said vacillation plane, and fifth andsixth cleaning and stabilizing air discharge orifices in said nozzlebody and associated with said third liquid discharge orifice, said fifthand sixth pattern air discharge orifices arranged 180° apart on oppositesides of said third liquid discharge orifice and positioned 90° fromsaid fifth and sixth pattern air discharge orifices, said fifth andsixth cleaning and stabilizing air discharge orifices configured todirect pressurized cleaning and stabilizing air in a direction parallelto said third axis to clear airborne contaminants away from said thirdliquid discharge orifice and to stabilize the third bead of adhesive insaid vacillation plane.
 4. The nozzle of claim 1, wherein said first andsecond pattern air discharge orifices converge toward said first axis.5. The nozzle of claim 1, wherein said nozzle body further comprises aprojecting nozzle portion having an apex and a base, said first liquiddischarge orifice opening on said apex and said first and second patternair discharge orifices opening on said base.
 6. The nozzle of claim 5,wherein said first and second cleaning and stabilizing air dischargeorifices open on said apex.
 7. A device for dispensing a liquid adhesiveto materials used in the manufacture of nonwoven products, comprising: avalve body including an adhesive input passage including a valvemechanism operative to selectively allow and prevent adhesive flowthrough said adhesive input passage, a nozzle body coupled to said valvebody, said nozzle body having a liquid supply passage in fluidcommunication with said adhesive input passage to selectively receivethe adhesive flow and a first liquid discharge orifice in fluidcommunication with said liquid supply passage, said first liquiddischarge orifice extending along a first axis and configured todischarge a first bead of the adhesive, first and second pattern airdischarge orifices in said nozzle body and associated with said firstliquid discharge orifice, said first and second pattern air dischargeorifices arranged 180° apart on opposite sides of said first liquiddischarge orifice and configured to direct pressurized pattern air atthe first bead of adhesive discharged through said first liquiddischarge orifice thereby vacillating the first bead of adhesive backand forth in a vacillation plane containing the first and second patternair discharge orifices, and first and second cleaning and stabilizingair discharge orifices in said nozzle body and associated with saidfirst liquid discharge orifice, said first and second cleaning andstabilizing air discharge orifices arranged 180° apart on opposite sidesof said first liquid discharge orifice and positioned 90° from saidfirst and second pattern air discharge orifices, said first and secondcleaning and stabilizing air discharge orifices configured to directpressurized cleaning and stabilizing air in a direction parallel to saidfirst axis to clear airborne contaminants away from said first liquiddischarge orifice and to stabilize the first bead of adhesive in saidvacillation plane.
 8. The device of claim 7, wherein said nozzle bodyfurther comprises: a second liquid discharge orifice in fluidcommunication with said liquid supply passage, said second liquiddischarge orifice extending along a second axis and configured todischarge a second bead of the adhesive, third and fourth pattern airdischarge orifices in said nozzle body and associated with said secondliquid discharge orifice, said third and fourth pattern air dischargeorifices arranged 180° apart on opposite sides of said second liquiddischarge orifice and positioned in said vacillation plane, said thirdand fourth pattern air discharge orifices configured to directpressurized pattern air at the second bead of adhesive dischargedthrough said second liquid discharge orifice thereby vacillating thesecond bead of adhesive back and forth in said vacillation plane, andthird and fourth cleaning and stabilizing air discharge orifices in saidnozzle body and associated with said second liquid discharge orifice,said third and fourth pattern air discharge orifices arranged 180° aparton opposite sides of said second liquid discharge orifice and positioned90° from said third and fourth pattern air discharge orifices, saidthird and fourth cleaning and stabilizing air discharge orificesconfigured to direct pressurized cleaning and stabilizing air in adirection parallel to said second axis to clear airborne contaminantsaway from the second liquid discharge orifice and to stabilize thesecond bead of adhesive in said vacillation plane.
 9. The device ofclaim 8, wherein said nozzle body further comprises: a third liquiddischarge orifice in fluid communication with said liquid supplypassage, said third liquid discharge orifice extending along a thirdaxis and configured to discharge a third bead of the adhesive, fifth andsixth pattern air discharge orifices in said nozzle body and associatedwith said third liquid discharge orifice, said fifth and sixth patternair discharge orifices arranged 180° apart on opposite sides of saidthird liquid discharge orifice and positioned in said vacillation plane,said fifth and sixth pattern air discharge orifices configured to directpressurized pattern air at the third bead of adhesive discharged throughsaid third liquid discharge orifice thereby vacillating the third beadof adhesive back and forth in said vacillation plane, and fifth andsixth cleaning and stabilizing air discharge orifices in said nozzlebody and associated with said third liquid discharge orifice, said fifthand sixth pattern air discharge orifices arranged 180° apart on oppositesides of said third liquid discharge orifice and positioned 90° fromsaid fifth and sixth pattern air discharge orifices, said fifth andsixth cleaning and stabilizing air discharge orifices configured todirect pressurized cleaning and stabilizing air in a direction parallelto said third axis to clear airborne contaminants away from said thirdliquid discharge orifice and to stabilize the third bead of adhesive insaid vacillation plane.
 10. The device of claim 7, wherein said firstand second pattern air discharge orifices converge toward said firstaxis.
 11. The device of claim 7, wherein said nozzle body furthercomprises a projecting nozzle portion having an apex and a base, saidfirst liquid discharge orifice opening on said apex and said first andsecond pattern air discharge orifices opening on said base.
 12. Thedevice of claim 11, wherein said first and second cleaning andstabilizing air discharge orifices open on said apex.